PowerMac G5 modification possibilities?

[RedCroissant]

Hello all,

It turns out that me selling my Quad is not easy and shipping costs are ridiculous (especially for what I would be including in the sale). So what I'm hoping to do is find a way to decrease energy consumption of the Quad and turn it into....a dual 2.5.

What I am wondering is: If it is possible to shut off one of the cores, will that possibly decrease energy consumption by at least 40%? If so, how would I go about doing that?

I cannot afford a "new" Mac, upgrades/repairs to my PowerBook, and shipping the quad with peripherals is almost prohibitively expensive.

Any ideas? I know I would be losing a lot of power, but even a dual 2.5 with 8GB RAM and a good GPU is far better than a single 1.25 with only 512MB RAM and so far kind of slow at everything.

Thanks in advance for any assistance/clarification/education...etc.

 

[flyproductions]

What I am wondering is: If it is possible to shut off one of the cores, will that possibly decrease energy consumption by at least 40%? If so, how would I go about doing that?

Isn't this as easy as unchecking as many cores as you want in the processors control panel, which was, as far as i remember, part of the developer/x-tools kit, included in the OS-discs? (picture attached)

And what it saves you should be easy to measure with something like that.

 

[jbarley]

Have a read at this article, lots of good info here.
Also just running the CPU's in reduced mode cuts the power requirements considerably.

 

[flyproductions]

Just tried the simple task of unchecking two of the cores of my quad and this seems to work. I ran a quick render test with cinebench 10 and the two deactivated cores stayed cool while the other two heated up and also the resulting score was only half of what i had with all 4 cores running. So at least reducing performance seems to work.

 

[RedCroissant]

Isn't this as easy as unchecking as many cores as you want in the processors control panel, which was, as far as i remember, part of the developer/x-tools kit, included in the OS-discs? (picture attached)

And what it saves you should be easy to measure with something like that.

View attachment 593852

Well this is awesome and didn't realize it was that straightforward! My question to you is, how do I get tho that control panel for the CPUs because I have the developer tools installed and not seeing that at all.

 

[Orizence]

Well this is awesome and didn't realize it was that straightforward! My question to you is, how do I get tho that control panel for the CPUs because I have the developer tools installed and not seeing that at all.

Just go to spotlight and search "processor" and install the prefpane

 

[RedCroissant]

Just go to spotlight and search "processor" and install the prefpane

Thank you. I feel kind of dumb now, but thank you very much!

 

[RedCroissant]

Is there a way to make this more permanent? As in, can I keep the other 2 CPUs off instead of having to turn them off each time I restart the machine?

 

[jbarley]

Is there a way to make this more permanent? As in, can I keep the other 2 CPUs off instead of having to turn them off each time I restart the machine?

Check out the included command line tool called "hwprefs", enter that title into a Terminal window and you'll see that you can enable-disable CPU's and a whole lot more.

 

[flyrod]

Also just running the CPU's in reduced mode cuts the power requirements considerably.

Will the G5 also run at half speed like the later G4's will? Is that what you're talking about with "reduced mode"?

 

[RedCroissant]

Well, this is awesome! I have only 2 cores enabled and the performance is completely fine for all of my daily tasks. The machine doesn't heat up nearly as much and the performance difference between the G5 and the powerbook is pretty drastic.

Thank you all for your help!

 

[flyrod]

Have you also tried the "reduced" mode?